PiCNN

PiCNN is a lightweight, open-source, single-header C++ library for Convolutional Neural Networks that is capable of running on single-board computers such as the RaspberryPi. It enables practical machine learning for Raspberry Pi programmers without the hassle, size, and computational requirements of installing and running larger machine learning frameworks. I developed this library during a past internship at the University of Cambridge’s Computer Laboratory.

Check out a brief presentation of PiCNN: PiCNN Presentation

Or take a look at the complete derivation of PiCNN: PiCNN

The source code is available here on GitHub.

Fixed-Wing UAV Flight Control System

I’m designing a complete flight control system from scratch. This includes the hardware, low- and high-level software, control and guidance algorithms, telemetry protocols, ground control station, etc.

Check out the source files on GitHub: https://github.com/pms67/HadesFCS

A video giving a broad overview of the hardware design:

Here’s a sneak peek of the hardware!

Low-Noise Headphone Amplifier

Low-noise, stereo-to-mono headphone amplifier. Pictures of the completed system can be seen below.

The amp consists of a set of input buffers, a summing amplifier, Baxandall volume stage, and finally a class AB output stage.

The PCB was designed in KiCAD.

DOWNLOAD THE SCHEMATIC HERE

It is rated for 9V but can be used with a supply voltage of up to 18V. Bandwidth (-3dB points) was designed to be from 20Hz to 20kHz when driving an 8 Ohm load. The amp can however drive larger loads easily, such as Beyerdynamic DT 880 Pro headphones at 250 Ohms.

The amplifier consists of four main sections:

  1. Power supply section: Reverse polarity protection, power supply filtering, bias voltage generation.
  2. Input buffers and summing: Simple NPN emitter followers (using standard BC547s) as high impedance buffers followed by a an approximately unity gain, op-amp summing amplifier (low-noise NE5532).
  3. Active volume control: This is a low-noise, Baxandall volume control (seen in Douglas Self’s book ‘Small Signal’) giving up to 17dB of gain.
  4. Output power amplifier: Finally, the output stage consisting of a unity gain op-amp buffer and a class AB power amplifier, capable of driving loads as small as 8 Ohms.

Self-Balancing Bicycle

As part of my final year at university, I built a full-scale rider-less, self-balancing bike. This involved the modelling, simulation, control system design, and mechanical/electrical/software implementation.

 

Read the final report by clicking here!

 

PID and H-Infinity controllers:

Full-scale bicycle test run:

Some pictures of the full-scale bicycle: